Public broadcaster NHK also warned residents to protect themselves and to stay away from unstable furniture.

Earthquake Early Warning alerts are sent to mobile phones, public speakers, radios and televisions in all the regions predicted to experience strong shaking.

This is not the first time a false alarm has triggered panic in Japan. In August 2016, an alert warned of a massive magnitude 9.1 earthquake that never came.

Japan is one of the most seismically active areas on Earth, accounting for about 20% of global quakes of magnitude 6.0 or greater. On average, seismometers are recording some kind of event in the country every five minutes.